In the processing of segments of tubular knitted fabric, such as sweater bodies and sleeves, for example, it has been conventional in the past to perform a so-called framing and steaming operation in order to adjust and stabilize the geometry of the segment. In a typical sweater body segment, for example, a cuff portion is knitted integrally to a body portion. The knit construction of the cuff portion is different from that of the body portion, to provide a somewhat more elastic region, and the cuff portion is intended to be somewhat smaller in circumference than the body portion of the segment in order to fit more snugly to the wearer. Up until the recent past, framing and steaming has been largely a one-at-a-time operation, involving significant manual labor. Sweater bodies and other similar segments were placed manually over a frame of appropriate shape, manually positioned and steamed, and then manually removed from the frame. The above mentioned Bryan patents represent a significant advance over theretofore known procedures, in that provisions are made for framing and steaming of individual, disconnected tubular segments on a continuously operating machine, in which the segments are fed in at one end and discharged at the other. This had not been successfully accomplished theretofore, because of the problems and difficulties resulting from the fact that different portions of the same segment have different construction and, in the finished product, are intended to have different geometry.
Pursuant to the inventions of the Bryan patents, tubular sweater segments and the like are applied to the upstream end of a propeller-spreader frame and are distended to a width determined by the desired width of the body portion of the segment--a width that is excessively large with respect to the cuff portion of the segment. After passing over the spreader frame, the segment is discharged onto a conveyor blanket and, after a very short intervening space, is gripped across its upper and lower layers by opposed, synchronously moving conveyor blankets. In the short interval between discharge from the spreader frame and engagement by the opposed blankets, the body of the sweater assumes the width desired for it, and the cuff portion contracts to a desired smaller size. Thereafter, the segment is conveyed, while still gripped, through a steaming zone, which serves to substantially stabilize the geometry of the segment. After steaming, the segment is released by the upper conveyor blanket and subjected to vertical agitation so as to be repetitively lifted clear of the lower conveyor blanket and permitted to adjust and stabilize further. The finished unit is discharged from the lower conveyor blanket and is ready to be manufactured into a sweater.
The method and apparatus of the present invention, is based directly upon the inventions of the above mentioned Bryan U.S. patents, but incorporates certain improvements therein. In particular, the present invention serves to substantially extend the operational range of the Bryan inventions, to be applicable to a greater variety of knitted constructions often utilized in the manufacture of sweaters and the like. Thus, for many popular knit constructions, it is either necessary or desirable to controllably lengthen the segment, as well as to controllably and differentially distend it laterally. The method and apparatus of the present invention, having the capability of doing that, is applicable to a much larger spectrum of types and styles of knitted constructions for sweaters and the like.
In accordance with one of the more specific aspects of the invention, provision is made for having a firm gripping engagement with the tubular segment, across its width, while the segment is still on the spreader frame. As leading portions of the segment are discharged from the spreader frame, they are gripped across the full width by opposed conveyor blankets, while trailing portions remain gripped by other means. Between the two gripped areas, a predetermined differential speed relationship may be maintained, in order to impart a desired lengthwise tension to the fabric. While under such tension, however, the fabric remains on the spreader frame throughout almost the entire distance, such that the uncontrolled narrowing of the fabric as a result of the tension is avoided. In order to effect the desired across-the-width gripping of the segment while still on the spreader frame, a unique form of telescopically adjustable, banded gripping roll is provided, which enables the fabric to be effectively gripped and controlled across its width, while it remains on the spreader frame, without regard to the adjusted width of the spreader frame.
In accordance with another specific aspect of the invention, provision is made for controllably varying the timing of the gripping engagement of the segment by the opposed conveyor blankets. The arrangement is such that, after discharge of the cuff portion of the segment from the spreader frame, an adequate interval of time is provided to enable a substantial adjustment and reduction in width of the cuff portion before the cuff is gripped by the conveyor blankets. After passage of the cuff, the opposed relationship of the conveyor blanket is adjusted, so that the body portion of the segment is gripped by the blankets substantially immediately as it is discharged from the spreader frame. While providing for the desired contraction of the cuff portion, this arrangement affords a greater degree of control over the width of the body portion and, at the same time, enables desired amounts of longitudinal tension to be applied to the body portion without uncontrolled loss of width.
In accordance with another aspect of the invention, provision is made for handling and processing of the tubular knitted segment while on the spreader frame, so as to minimize any distortion of cross lines which otherwise may tend to result from lateral distension of the fabric. To this end, the propeller-spreader system advantageously includes a dual belt arrangement, with the upstream belts advancing the fabric at a slightly greater rate of speed than it is removed by the downstream belts, to provide for a so-called overfeed of the fabric at the transition area. In addition, an air table is provided directly underneath the spreader frame to help support segments of substantial width against sagging, which might otherwise result in distortions from the sag itself, and/or friction and retarding by reason of contact of the sagging fabric with other parts of the machine.
In accordance with another and still more specific aspect of the invention, an advantageous form of decurling means is provided, which permits the unrestricted passage of the leading end of the sweater segment, but which engages at least the trailing edge portion of the segment in a manner to unfold any curl which may form in the trailing edge of the fabric during prior handling.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description and to the accompanying drawings.